The prior art discloses many types of systems for bending and/or tempering heated glass sheets such as is necessary, for example, with vehicle windows. One type of bending system includes a holder having a downwardly facing surface of a downwardly convex curved shape for receiving a heated glass sheet from a conveyor below the holder. After bending against the holder, a mold of the system receives the heated glass sheet for cooling.
U.S. Pat. No. 3,778,244 discloses a glass sheet bending system of the type described above whose holder is surrounded by a hood through which an aspirator draws gas in order to provide bending of a heated glass sheet against the holder surface. After such bending, the glass sheet is received by a mold which is then moved to a cooling chamber where annealing of the bent glass sheet takes place.
U.S. Pat. No. 4,282,026 discloses a glass bending and tempering system having one embodiment including a holder with a curved surface against which auxiliary lifters engage and bend a heated glass sheet received from a conveyor below the holder. After such bending, an open center mold having a greater curvature than the holder surface receives the heated glass sheet for additional bending under the operation of gravity. An actuator moves the mold from the holder to an adjacent quench unit with the bent glass sheet thereon in a time to control the extent of bending before tempering of the glass sheet at the quench unit.
U.S. Pat. No. 4,204,854 discloses a glass sheet bending system including a plurality of gas jet pumps that receive a primary inflow of gas and produce an amplified secondary outflow of gas upwardly from below a conveyor against a heated glass sheet on the conveyor below a holder of the system. Certain of the embodiments disclosed have a holder of a downwardly convex curved shape such that the upward gas flow bends the heated glass sheet against the curved holder.
U.S. Pat. Nos. 4,202,681 and 4,222,763 disclose glass sheet bending systems including gas jet pumps utilized to draw a vacuum through the surface of a holder that receives a heated glass sheet from a conveyor for bending.